1. Field of the Invention
The present invention relates to swing-type check valves for use in pipelines and the like. The invention, more particularly, concerns a removable clapper support member from which a check valve clapper may be pivotably suspended. The present invention concerns a check valve clapper hanger which may be easily installed in and removed from a check valve housing and which provides bearing surfaces for the swinging movement of the clapper.
2. Description of the Prior Art
The most common type of check valve is a swing check valve consisting of a clapper pivotably mounted or hinged inside a check valve housing. Various methods of so mounting the clapper inside a check valve housing are known in the art. These methods employ various hinging arrangements.
In conventional swing check valves, the hanger mechanism from which the clapper is suspended is often an integral part of the valve housing. This type of integral structure unfortunately tends to substantially increase the complexity and cost of making the housing. The increased cost and complexity result from the interrupted cuts that are required in order to machine the clapper hanger in the housing.
Integral formation of the clapper hanger in the check valve housing also necessitates that the clapper hanger be made from the same material as the housing. In certain instances, particularly in highly corrosive or caustic environments, it may prove desirable to have a clapper hanger made with a higher quality, more expensive material than that used in the housing. Unfortunately, in integral hanger/housing structures, this requires that the same high quality metal alloys required for the clapper hanger also be used for the entire valve housing.
Other types of conventional check valves have employed removable clapper hangers. These check valves, however, have not met with wide success because they have been unable to retain the check valve clapper in its proper position inside the check valve housing.
Another drawback of conventional check valves employing removable clapper hangers is the complex, multi-step assembly process required to install the clapper in the clapper hanger. This multi-step process is necessitated by the fact that the clapper is suspended from a horizontally mounted cylinder or hinge which is mounted in adjacent holes in the clapper hanger. Such a configuration is shown in U.S. Pat. No. 3,060,961 to Conley and U.S. Pat. No. 2,923,317 to McInerney. Installation of the clapper disclosed in these two patents requires alignment of the holes in the clapper and clapper hanger followed by insertion of the hinge member through these holes. Disassembly of such a clapper valve requires the repetition of these steps in reverse order. The time required to perform this procedure increases the installation and maintenance costs of such valves.